It's ok if you haven't played any of the beforehand games, Skyrim doesn't relate to them a whole lot. There will be references to events in the past games that if you played them you'll get, and you'll have a better understanding of how the world works but other then that you should be fine. I actually played the last three elder scrolls in this order. Skyrim, Oblivion, Morrowind. Haven't played daggerfall or arena yet.

Start with Skyrim. Learn about modding. It's great modding Skyrim, but can easily lead to tears and broken saves.

Skyrim is the easier game to play and most modern. Morrowind is in some ways a "better" game, but it's less intuitive. Maybe if you come from tabletop roleplaying it's easy, but I find it a hassle having to carefully control my levelling up in Morrowind, because...

You should probably start with Morrowind though it's the hardest to start and understand. No fast travel or markers and no quest arrows. It's one of the best games made but it doesn't hold your hand. I'd start with this one just because the graphics are dated and you might not want to play it after Skyrim.

I'd try Oblivion 2nd. I still like that game a lot, very varied terrain and cities.

Morrowind with MGSO 3.0 (graphics overhaul) is amazingly beautiful and graphically comparable to much more modern games. If you are a confident gamer and a patient person, you may well love it the most. Many people do.

I started with Skyrim and I've now got Morrowind and Oblivion. Skyrim is pretty immersive in itself (so it can be played as a stand alone game) but after going back and playing the earlier games and returning to replay Skyrim you feel more involved as a character and the history.

TL:DR If you enjoy Skyrim go and grab Morrowind and Oblivion to enjoy it even more :)

Start with Skyrim. It's more user-friendly and you'll be able to learn quickly about mods, which you really need if you plan to play Morrowind and Oblivion. You also have access to more information on Skyrim, as it is current. Then get yourself some Morrowind, because that's where the brilliance is. (Not that Skyrim isn't pretty stellar itself.) Whether or not you get oblivion depends on how much you love all this stuff.

I started with Skyrim and I've worked my way through the other games, Skyrim doesn't relate to them but there are references and some quests relating to the areas or history etc. So I just got super into ES and wanted to learn more. But you can basically start anywhere.

Start with Skyrim. It's more user-friendly and you'll be able to learn quickly about mods, which you really need if you plan to play Morrowind and Oblivion. You also have access to more information on Skyrim, as it is current. Then get yourself some Morrowind, because that's where the brilliance is. (Not that Skyrim isn't pretty stellar itself.) Whether or not you get oblivion depends on how much you love all this stuff.

personally i found morrowind more user friendly. Its designed for PC,it doesnt have the horrible clunky console UI of Oblivion (marginally made better in skyrim)

Start with Skyrim. A large immersive world, great graphics and accessible gameplay. Don’t bother with mods on your first play trough. I would also get the Dawnguard DLC since it’s integrated in the main game and adds a little flavor. Hearthfire is a nice addition, but doesn’t really add much in terms of gameplay.